A 58-year-old man was in police custody Friday after stabbing a man in Chinatown, authorities said.

The incident happened as the suspect was arguing with the 42-year-old victim at about 9:30 p.m.

The suspect attacked the victim with an unknown weapon, causing the victim substantial injuries, police said.

An Emergency Medical Services report said responders treated the victim, who had been stabbed by an unknown object, at Smith and North Hotel streets. He was taken in serious condition to the Queen’s Medical Center.

Police arrested the suspect at the intersection of North Hotel Street and Kekaulike Mall for investigation of second-degree assault.